Microbiological results from milk samples obtained premilking and postmilking for the diagnosis of bovine intramammary infections.

Bacteriological culture results were compared between 336 pairs of quarter milk samples collected premilking and postmilking. Using a positive result on either premilking or postmilking samples as the definitive diagnosis, premilking sampling sensitivity was 91% for Staphylococcus aureus, 91% for coagulase-negative staphylococci, and 97% for Streptococcus other than agalactiae. Postmilking sampling sensitivities were 81, 45, and 58%, respectively, for the same pathogens. Requiring both premilking and postmilking samples for the definitive diagnosis, specificities were 92, 86, and 95% for premilking sampling alone and 96, 98, and 99% for postmilking sampling alone. Such differences in specificity would result in major differences in predictive value of a positive culture for herds with a low prevalence. Multiple isolates were significantly more common from premilking samples.     

Changes in optical properties caused by UV-irradiation of aquatic humic substances from the amazon river basin: seasonal variability evaluation

Aquatic humic substances (AHS) isolated from two characteristic seasons of the Negro river, winter and summer corresponding to floody and dry periods, were structurally characterized by 13C nuclear magnetic ressonance. Subsequently, AHS aqueous solutions were irradiated with a polychromatic lamp (290-475 nm) and monitored by its total organic carbon (TOC) content, ultraviolet-visible (UV-vis) absorbance, fluorescence, and Fourier transformed infrared spectroscopy (FTIR). As a result, a photobleaching up to 80% after irradiation of 48 h was observed. Conformational rearrangements and formation of low molecular complexity structures were formed during the irradiation, as deduced from the pH decrement and the fluorescence shifting to lower wavelengths. Additionally a significant mineralization with the formation of CO2, CO, and inorganic carbon compounds was registered, as assumed by TOC losses of up to 70%. The differences in photodegradation between samples expressed by photobleaching efficiency were enhanced in the summer sample and related to its elevated aromatic content. Aromatic structures are assumed to have high autosensitization capacity effects mediated by the free radical generation from quinone and phenolic moieties.     

Partially imidized,water-soluble polymeric amides. I. Partially imidized polyacrylamide and polymethacrylamide

Five to six million molecular weight polyacrylamide and polymethacrylamides of comparable post-alkaline hydrolysis viscosities were imidized by dissolution and heating in 6N HCl. After alkaline hydrolysis, the imidized polymers demonstrated significantly better retention of viscosity to 2% NaCl than did similar partially hydrolyzed polymers. Viscosities in 0.01% NaCl and resistance to shear were not markedly affected by this modification. It is assumed that this improved performance in brine is the result of chain stiffening due to intrachain imide rings.     

An experimental study of the effect of sheet thickness and grain size on limit-strains in biaxial stretching

Effects of grain size on the limiting strains attained in biaxial stretching have been investigated using 70% Cu-30% Zn brass sheets of 1.0 and 0.5 mm thickness with regular grain structures. The limit-strains were closely related to the ratio of sheet thickness, t_o, to average grain diameter, d_o, over a range of t_o/d_o between 2 and 30. In the earlier stages of stretching, growth in the amplitude of surface roughening was independent of t_o and close to being proportional to d_oε₃ where ε₃ is thickness strain in equibiaxial stretching. The diffuse instability strain was rather insensitive to the effects of the short-range strain inhomogeneities developed during such stable extension. Surface roughening became sensitive to t_o at an applied strain ε_3c which decreased with decreasing t_o/d_o. In stretching beyond ε_3c macroscopic strain localisation became established in the form of a network of surface grooves. It is concluded that the influence of grain anisotropy on limit-strains in biaxial stretching cannot be predicted in the terms of available continuum models of defect growth. An attempt is made to identify the dominant material and geometric factors which control the onset of localised necking when grain anisotropy is the principal source of inhomogeneous straining.     

Milk production change following clinical mastitis and reproductive performance compared among J5 vaccinated and control dairy cattle

Naturally occurring cases of bovine clinical mastitis (CM) were studied among J5 vaccinates and controls on 3 commercial dairy farms. Milk production change and reproductive performance following CM were compared between the 2 groups. Among 306 controls and 251 vaccinates, there were 221 new cases of CM affecting 120 cows; 437 lactations never had a case of CM. Environmental pathogens made up 90% (159/176) of etiologic agents isolated. Change in daily milk production following CM was associated with J5 vaccination, days in milk (DIM) at onset of CM, and herd effect as well as each 2-way interaction between the 3 factors. The adjusted daily milk for 21 d following CM was 7.6 kg greater among J5 vaccinates than controls; however, this protective effect of vaccination waned with increasing DIM at onset of CM. A mixed linear model with autoregressive order 1 [AR(1)] correlation structure estimated the daily milk production of any cow (whether or not she had CM) on a given DIM. Cows with CM caused by nonagalactiae streptococci, Staphylococcus aureus, Escherichia coli, or Klebsiella lost significant daily milk production for the entire lactation relative to nonmastitic cows. Another mixed linear model for only coliform CM cases (E. coli, Klebsiella, and Enterobacter) within the first 50 DIM showed milk loss for 21 d following coliform CM to be significantly less for J5 vaccinates than for controls, by 6 to 15 kg per day. Cows were significantly less likely to become pregnant if they had CM caused by E. coli (42% pregnant) or Streptococcus spp. (38% pregnant), whereas 78% (342/437) of cows with no mastitis conceived. Days open (number of days from calving until pregnancy) averaged 131 d for cows with no CM and 162 d for cows that had at least one case of CM. Days until conception, days until last breeding, days open, times bred, and percentage of cows pregnant by 200 DIM were not changed with J5 vaccination. Nonetheless, an important benefit of the use of J5 bacterin appears to be reduction of the loss of daily milk production following CM, whether all cases or only those caused by coliform bacteria were considered.     

Influence of slaughter weight and stress gene genotype on the water-holding capacity and protein gel characteristics of three porcine muscles

The longissimus lumborum, gluteus medius, and the triceps brachii muscles from 40 animals were used to evaluate the effect of stress gene genotype (non-mutant, NN and mono-mutant, Nn) and live weight at slaughter (110 kg and 140 kg) on the processing quality of fresh pork. The 45 minute and ultimate pH measurements did not differ between genotypes. Total percent protein was not different between samples taken from NN or Nn pigs, nor were there any differences in salt-soluble protein. The M. longissimus lumborum from Nn pigs possessed lower water-holding capacity values and lost greater amounts of water upon cooking. In addition, Nn pigs had lower subjective color and firmness scores which suggest a higher incidence of pale, soft and exudative pork. Slaughter weight did not affect total protein, salt-soluble protein, Minolta L(?), a(?) and b(?) values or subjective color, firmness and marbling scores. Back fat thickness and loineye area increased as slaughter weight increased. Overall, this study suggested that Nn pigs have reduced water retention properties which may result in lower yields in processed meat items. Slaughter weight had limited effects on the processing quality of meat from NN or Nn pigs. There were no interactions of significance between stress gene genotype and slaughter weight, suggesting that the differences in muscle quality and functional properties between NN and Nn pigs are maintained over the slaughter weights used in this study.     

Determination of ciprofloxacin and nalidixic acid resistance in Campylobacter jejuni with a fluorogenic polymerase chain reaction assay

A fluorogenic polymerase chain reaction assay for the gyrA gene was used to determine the frequency of a Thr-86 mutation in Campylobacter jejuni isolates from food animals and humans in northern Thailand and to investigate the correlation between this mutation and bacterial resistance to fluoroquinolones. Eighty-four isolates of C. jejuni were used: 65 from healthy chickens on farms, 16 from chickens at the slaughterhouse, 1 from chicken meat at the market, and 1 from a healthy farm worker. The microbroth dilution technique was used for in vitro susceptibility testing. MIC breakpoints established by the National Antimicrobial Resistance Monitoring System were used to categorize the resistance of C. jejuni to ciprofloxacin and nalidixic acid. Sixty of the 84 C. jejuni isolates tested carried the Thr-86 mutation in the gyrA gene. All isolates with ciprofloxacin MICs of > or = 2 mg/liter carried the mutation, and no isolates with nalidixic acid MICs of < or = 16 mg/liter carried the Thr-86-to-Ile mutation. There was a very strong association between ciprofloxacin resistance and the presence of the mutation (kappa = 0.971, P < 0.01). The association between the presence of the Thr-86-to-Ile mutation and nalidixic acid resistance was weaker (kappa 0.859: P < or = 0.01).     

Molecular interfacial reactions between Pu(VI) and manganese oxide minerals manganite and hausmannite

The sorption of Pu(VI) onto manganite (MnOOH) and hausmannite (Mn3O4) was studied as a function of time, solution pH, and initial plutonium concentration. Kinetic experiments indicate that the surface complexation of plutonium occurs over the first 24 h of contact with the mineral surface. The sorption increases with pH beginning at pH 3 until it reaches a maximum value of 100% at pH 8 (0.0011-0.84 micromol of Pu/m2 of manganite and 0.98-1.2 micromol of Pu/m2 of hausmannite) and then decreases over the pH range from 8 to 10. The ratio of solid to solution was 10 mg/mL for manganite experiments and 4 mg/mL for hausmannite samples. Carbonate was not excluded from the experiments. The amount of plutonium removed from the solution by the minerals is determined by a combination of factors including the plutonium solution species, the surface charge of the mineral, and the mineral surface area. X-ray absorption fine structure taken at the Pu L(III) edge were compared to plutonium standard spectra and showed that Pu(VI) was reduced to Pu(IV) after contact with the minerals. Plutonium sorption to the mineral surface is consistent with an inner-sphere configuration, and no evidence of PuO2 precipitation is observed. The reduction and complexation of Pu(VI) by manganese minerals has direct implications on possible migration of Pu(VI) species in the environment.     

Congruity theory and linear models of attitude change.

Evaluated C. E. Osgood and P. H. Tannenbaum's (see record 1955-08361-001) congruity model of attitude change, a regression model derived from the Osgood and Tannenbaum model, and D. R. Heise's (see record 1969-08323-001) 3 general linear models of attitude change, using data obtained from 208 undergraduates. 104 Ss rated 8 3-word (subject, verb, object) sentences 1st, and then rated the individual words. The other Ss rated the individual words 1st. The mean ratings for the 2 groups were compared to obtain the attitude change for each element, and the models were used to predict the change which resulted from the combination of the words into a sentence. Sex differences were found in mean attitudinal evaluations, and the inclusion of higher-order interaction terms increased the predictability of attitude ratings for females more than for males. Heise's Model III was the best predictor of attitude change, followed by his Model II and the regression model derived from the Osgood and Tannenbaum model. The Osgood and Tannenbaum model gave poor prediction of the mean attitudinal changes obtained. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SUBSTITUTION OF TOPAZ,DOMESTIC KYANITE,AND SYNTHETIC MULLITE-CORUNDUM FOR INDIA KYANITE,I–III*

This report on the utilization of domestic materials as replacements for India kyanite has been divided into four parts, namely, (I) kyanite and other high-grade refractories, (II) effect of heat on kyanite and topaz, and (III) load resistance of refractories at elevated temperatures; (IV) will be published later.